International audienceMany experimental techniques and many com- mercial solutions have been proposed to realize non-contact 3D digitization of industrial objects. Unfortunately, the per- formances of active 3D scanners depend on the optical prop- erties of the surface to digitize. That is why the results obtained by active 3D triangulation on specular or transparent surfaces are not as good as those obtained on diffuse surfaces. In this paper, we present the developments we have realized to address highly reflective metallic surfaces. These develop- ments are based on the extension of a technique, called "Scan- ning from heating" and initially dedicated to glass material. In comparison to conventional active triangulation techniques that measure the reflection of visible radiation, we measure here the thermal emission of a surface, which is locally heated by a laser source. We describe in this paper the successive steps we have followed to adapt Scanning From Heating to metallic materials, to evaluate the performances and finally to develop an operational prototype

3D vision is an area of computer vision that has attracted a lot of research interest and has been widely studied. In recent years we witness an increasing interest from the industrial community. This interest is driven by the recent advances in 3D technologies, which enable high precision measurements at an affordable cost. With 3D vision techniques we can conduct advanced manufactured parts inspections and metrology analysis. However, we are not able to detect subsurface defects. This kind of detection is achieved by other techniques, like infrared thermography. In this work, we present a new registration framework for 3D and thermal infrared multimodal fusion. The resulting fused data can be used for advanced 3D inspection in Nondestructive Testing and Evaluation (NDT&E) applications. The fusion permits the simultaneous visible surface and subsurface inspections to be conducted in the same process. Experimental tests were conducted with different materials. The obtained results are promising and show how these new techniques can be used efficiently in a combined NDT&E-Metrology analysis of manufactured parts, in areas such as aerospace and automotive.

For the past two decades, the need for three-dimensional (3-D) scanning of industrial objects has increased significantly and many experimental techniques and commercial solutions have been proposed. However, difficulties remain for the acquisition of optically non-cooperative surfaces, such as transparent or specular surfaces. To address highly reflective metallic surfaces, we propose the extension of a technique that was originally dedicated to glass objects. In contrast to conventional active triangulation techniques that measure the reflection of visible radiation, we measure the thermal emission of a surface, which is locally heated by a laser source. Considering the thermophysical properties of metals, we present a simulation model of heat exchanges that are induced by the process, helping to demonstrate its feasibility on specular metallic surfaces and predicting the settings of the system. With our experimental device, we have validated the theoretical modeling and computed some 3-D point clouds from specular surfaces of various geometries. Furthermore, a comparison of our results with those of a conventional system on specular and diffuse parts will highlight that the accuracy of the measurement no longer depends on the roughness of the surface. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

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